In the development of the technology of downsizing electronic apparatus, examples of which are; flat panel displays, arrays of switching or storage elements and discrete wiring, the trend in reduction of size is approaching conductor sizes of 100 micrometers in width and is resulting in a need for a bridging interconnection technique for a bridging element that is to be placed across an interuption in a conductive member on a substrate. The bridging element may be varied in shape and size and the location for the bridging may be such that compatibility with standard mass production techniques is limited. As two specific examples; in a first example,in large deposited wiring layouts a flaw in a single conductor can jeopardize the usefulness of the entire layout but a repair would require providing a single patch at a location in a mass produced and spaced array; and, as a second example in many arrays parallel circuitry is arranged when the array is made so that the parallel circuitry can be connected in as a repair for a failure in a portion of the array. In each of these types of examples a single location must be found and a bridging member connected in that joins conductive members. Such an operation requires a technique developing in the art of single point microbonding.
Single point microbonding requires precise alignment and positioning of the elements to be bonded. The operation has to take place at a location governed by what is being repaired or bridged and seldom can be predicted in advance, and the precise shape and size of the bridging part that will be needed also cannot be predicted. In some applications spheres are involved while in others small discs and pieces of wire are used.
There has been some attention directed to ball and line repair in the art.
For repair of interruptions in thin film lines. In one technique microwire segments are fabricated on thin polymer carriers and the polymer sheet is manipulated so that the microwire is located exactly over the interruption and bonded in place. This technique is illustrated in U.S. Pat. No. 5,079,070. In another technique a conductive repair patch is transported and released into a prepared location by a carrier tool. This technique is illustrated in U.S. Pat. No. 5,289,632.
In still another technique, in active line repair in display circuitry, a disc is bonded across two adjacent pads so positioned for connecting in alternate circuitry. This technique is illustrated in U.S. Ser. No. 08 (639,583) Apr. 29, 1996.
For repair of a missing solder ball in a pad array involving a chip, a solder ball is melted and attached to a heating tip coated with a solder wetting material then positioned and attached on the defective pad. This technique is illustrated in IBM TDB Vol. 39 No. 7 July 1996 p. 281.
At present no tool has been developed that is versatile enough to handle the many bridging shapes and be able to place them in the one at a time unique locations in the various applications without retooling and the sizes are much too small for any manual operations.